Bleaching composition and process



Patented Jan. 17, 1933 EDWARD H. MANAHAN, OF

MOUNTAIN LAKE, NEW JERSEY,

Arm ARTHUR 0. 3011mm,

OF RICHMOND HILL, NEW YORK BLEACHING CO'MYOSI No Drawing.

This invention relates to a bleaching composition and a process of bleaching materials and is applicable to the bleaching of fur or hair or fur skins or other materials, such as felts, straw, oil and textiles, for example. It is also applicable to tanned hides or skins with the fur or hair thereon whether they have been otherwise treated or not. The invention is especially suitable for bleaching such furs as rabbits, squirrels, dogs and foxes, but is. not restricted to these sorts of skins.

Heretofore solutions of hydrogen peroxide or hydrogen peroxide liberating substances have been used for bleaching furs and the like, the solutions being either in neutral, slightly acid or alkaline condition. Such bleaching solutions require several hours, are wasteful of hydrogen peroxide, and are-not satisfactory for certain sorts of furs or other substances that are difiicult to bleach.

We have found that we can produce a more active and satisfactory bleaching composition by adding certain substances to a slightly alkaline aqueous solution containing hydrogen eroxide or a substance capable of yielding hydrogen peroxide. Our investigations have led us to believe that such substances are compounds which contain two oxygen atoms linked together in their molecular structure and are capable of forming unstable addition compounds with hydrogen peroxide. This sort of substance seems to us to cause a particular kind of hydrogen peroxide decomposition by which oxygen is liberated in a much more active form than is the case with the usual normal decomposition of hydrogen peroxide or by its decomposition in the presence of such oxidizing compounds as manganates, chromates, vanadates, etc., but We do not Wish to commit ourselves to any par ticular theory to account for the results that we have obtained.

We have succeeded in carrying out our invention by adding persulphate, such as ammonium or potassium persulphate to a solution of hydrogen peroxide or a compound capable of liberating hydrogen peroxide, the solution being slightly alkaline or being made so after the addition of the persulphate. In

Application filed July 28, 1928.

TION AND rnocnss Serial No. 296,990.

this manner, we have produced a much more active bleaching solution. Such a bleaching solution not only causes satisfactory bleaching results to be obtained upon the usual materials in a few hours, but also bleaches certain furs upon which hydrogen peroxide alone will not produce satisfactory results. Perborates may be used instead of the persulphatesbut usually with less efiicient results. Experience has shown that certain oxidizing-agents, such as chromates, dichromates, manganates, chlorates, vanadates and compounds of metals that have more than one valence, such as iron and copper, do not have the effect of appreciably increasing the bleaching action of hydrogen peroxide.

We have found that although persulphates or perborates alone, in an alkaline solution, Willnot produce any appreciable bleaching action on certainsubstances, such as rabbit furs, for example, these substances can readily bleached by the persulphate (or perborate) and hydrogen peroxide together.

The per-sulphate or perborate appears to act as a catalyzer for the decomposition of hydrogen peroxide in such a manner that decomposition of the same seems to take place in amanner that is different from that which normally takes place when hydrogen peroxide is decomposed. The persulphate or perborate does not seem to decompose with an evolution of the available oxygen during the bleaching operation but seems to form an addition compound with the hydrogen peroxide, which addition compoundseems to decompose into a persulphate, water and a form of oxygen that is very active for bleaching purposes.

' We have also found that the addition of certain salts, such as sodium pyrophosphate to an alkaline solution of hydrogen peroxide or hydrogen peroxide liberating substances and persulphate to perborate gives advantageous results in certain instances. The presence of the pyrophosphate in the solution seems tocause. a larger proportion of the hydrogen peroxide to undergo the more eifective form of decomposition and thereby cause a large saving in the amount of hydrogen peroxide that is requiredfor the bleaching operation.

The following is given as a specific example of carrying out the invention but it is to be understood that the invention is not limited to the particular substances or propor- 5 tions enumerated. A solution is made up containin about 2 ounces of potassium persulphate or each gallon of 5 volume hydrogen peroxide or approximately 1 per cent hydrogen peroxide in the aqueous solution.

The solution may be made slightly alkaline by adding, say, 2 ounces of potassium carbonate per gallon of the solutlon.

Such a solution is suitable for bleaching animal furs, for example, such as rabbits,

5 squirrel, do s, foxes, etc. The furs may be bleached by ringing them into contact with the solution for a few hours, the temperature preferably being maintained at about 80 to 90 F. For instance a rabbits fur may be bleached by immersing it in the solution for about three hours. a

By adding about 2 ounces of sodium pyrophosphate to the solution, the amount of hydrogen peroxide that has to be decomposed to produce the desired bleaching effect is considerably reduced. The strength of the hydrogen peroxide solutioncan be varied'over wide ranges with good results and other persulphates may be used, such as ammonium or sodium persulphate, for example, and other alkalies can be used for making the solution alkaline, such as sodium carbonate, ammonium hydroxide and tri-sodium phosphate, for example. The concentration of the various constituents may be altered through wide limits. The bleaching action is 1generally more rapid and intense with the igher concentration of the persulphate and h drogen peroxide, and the rapidity of the bleachmg action also increases with an in v crease in the temperature. The proper concentrations and conditions for best efl'ectsdepend to some extent upon the nature of the substances to be bleached and can be readily ascertained by trial.

We claim:

1. A bleaching composition for furs, comprising an alkaline aqueous solution of about 1 of hydrogen peroxide, and about two ounces of a persulphate and about two ounces of sodium pyrophosphate for each gallon of the solution.,

2. A bleaching composition for furs, comprisin an aqueous solution of about 1%% of hy rogen peroxide, and about two ounces of a persul hate, about two ounces of sodium pyrophosp ate and about two ounces of an alkallne salt for'each gallon of the solution.

3. Theprocess ofbleaching furs which comprises treating them with an aqueous alkaline solution of hydro en peroxide, a ersulphate and sodium pyrop osphate while eeping the temperature below about F.

EDWARD H. MANAHAN. ARTHUR C.- JOHANN. 

